Presently there are two methods of growing mushrooms commercially, the shelf and the tray methods. In the tray method, mushrooms are grown in wooden trays which range in size from about 4 ft..times.4 ft. to about 4 ft..times.8 ft. The major advantage of the tray method over the shelf method has been the ability to mechanize all of the mushroom growing operations. This ability lowers the use of manual labor in moving material. Drawbacks of tray systems include damage to the trays and high initial and replacement costs. In moving the heavy trays from one machine to the next and from room to room, considerable wear and tear on the trays is experienced due to the weight of the compost in the trays. The tray handling machinery is costly and requires qualified electricians and fitters to maintain the machinery. Damage to wooden trays, costly machinery and the need for full-time electricians and fitters result in very high operating costs using the tray method.
Until recently, in the shelf method, all of the mushroom growing operations, including filling, spawning, casing, picking and emptying of the shelves, were accomplished manually. This has mainly been due to the size and shape of the existing buildings. Mushroom growers have continued to use these old, manual methods in their existing buildings rather than face the expense of building entirely new houses and attempting to mechanize the various operations. In a typical mushroom house utilizing the shelf method, mushrooms are grown in shelves which are about 65 inches (165 cm) wide and about 60 ft. (18.3 m) long. These shelves are usually stacked in the mushroom house in tiers, six or so in a tier, and in adjacent tiers. The tiers are about 12 ft. (3.66 m) high. The vertical distance between shelves is about 24 inches (61 cm). The dimensions of mushroom buildings, however, often vary from plant to plant. Several of the above-mentioned tiers may be placed in a growing room. The aisles between adjacent tiers are generally no more than 32 inches (0.81 m) wide. The distance from the top of the top shelf to the ceiling of the mushroom house is usually limited to about 3 ft. (0.915 m). At the ends of each tier, only about 3 ft. (0.915 m) of space is left between the tiers and the respective walls of the building. Further complicating the problems in present mushroom houses, from a material handling standpoint, is the fact that the access into these growing rooms usually is a door which is about 32 inches (0.81 m) wide and only 6 ft. (1.83 m) high. The above description makes it clear that room for machinery and attendant personnel is very limited and, for this reason, mushroom growing operations have previously been limited to time consuming, arduous manual labor. Further, the compact arrangements just described are typical, and desirable in other respects, since much of the success of a commercial growing operation depends upon proper use of heat, air and other environmental factors which are relatively easy to control in present houses. Since there are a large number of commercial shelf systems in use, the need for mechanization has been and is great.
In the cultivation of mushrooms using the shelf method, a growing medium, compost, is first placed in the above-mentioned shelves to a depth of about 12 inches (30.5 cm). After all of the shelves in a growing room are filled with the compost, the room is sealed, and the compost is allowed to heat up, thereby completing pasteurization. After pasteurization, the compost is spawned (planted with the mushroom seed). Approximately 14 days after spawning, the compost is covered with a layer of soil, or casing, to induce fruiting of the mushrooms. When the mushrooms are grown, they are harvested by hand, and the mushroom beds are removed, again generally by hand, and the cycle is begun again, i.e. filling, spawning, casing, etc.
In the past, as previously mentioned, filling of the shelves with compost was usually accomplished manually. An attempt at mechanization of this operation is described in U.S. Pat. No. 3,936,975 (deWinter). Therein, a bed for growing mushrooms is disclosed wherein the compost is deposited at one end of the shelf onto two webs, an upper and a lower web, the lower web being of considerably more open weave than the fabric of the upper web. The upper web, upon which the compost is being directly deposited, is moved lengthwise of the shelf, sliding on the lower web which is stationary. When the growing cycle is completed, the growing medium can be removed at the end of the shelf by again sliding the upper web toward the removal end and off the shelf.
A method of mechanizing the composting and the above-mentioned casing step is disclosed in my pending patent application, Ser. No. 879,903. Therein, a reversible belt and auger are utilized to distribute a uniformly thick layer of casing on the top of the layer of compost at the proper time, or such apparatus may be utilized to distribute the compost. The invention disclosed therein does not utilize the key elements of the instant invention, i.e. the belt moving along the bottom of the shelf and acting cooperatively with the reversible, variable speed cross conveyer and the bladed leveling member of the present invention.
The present invention provides an improved, automated method and apparatus for laying compost in a mushroom shelf which, at relatively low cost, considerably reduces the manual labor required in the past and provides a very uniform depth of compost along the entire shelf length.